Vapour barrier for kitchen reno

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Posted by: from Saskatoon
9/7/2016 at 12:03:59 PM

We are doing a reno in our kitchen. It has popcorn ceiling. We would also like to add recessed lighting.

My question is about the vapour barrier. There is currently a 2mm vapour in attic. Can you add a vapour barrier below the existing drywall and add new drywall?

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Christopher from Mint Roofing Ltd. in Whitby
Date/Time9/7/2016 at 1:13:28 PM

No, that would trap any moisture between both and become problematic quickly.

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Matthew from Matt of All Trades in Kitchener
Date/Time9/7/2016 at 7:32:03 PM

Agreed. One layer only. Can double the plastic layers but do not sandwich the drywall.

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Date/Time9/7/2016 at 8:20:46 PM

I've never heard or thought of doing that. So great question but the answer is no you cannot place vapour between the drywall. The 2 mil poly is garbage and it's not even close to being a true vapourbarrier that will hold heat in your home and the reverse hold the heat from coming in your home from the attic space. So mould needs a paper source to grow and placing the poly between the drywall will be leaving your attic space wide open for mould problems in the future. You need to remove drywall. 2 mil (sandwich wrap) accoustical seal the perimeter and poly ceiling with 6 mil poly / tape all seams. Then drywall re blowin attic space. Renos should only be done the right way or you'll regret and start all over a few years down the road.



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Date/Time9/7/2016 at 8:41:12 PM


Rory from Compass Construction. Existing vapour barrier appears to be too light 2mm? Not a big job to install and replace barrier and drywall.

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Ernie from Edj Decorating in Winnipeg
Date/Time9/7/2016 at 9:21:32 PM

No adding an in-between layer will cause moisture to get trapped then mold sets in an causes way to many problems.

You can add blow in insulation to get r value to 50 or tear down re poly 6mm and re drywall.

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Date/Time9/8/2016 at 11:41:17 PM

No you would have to go back to the rafters and replace the vapour barrier. Depending on your attic you could look at spray foam on top as it will provide a vapour barrier.

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Jim in Saskatoon
Date/Time9/9/2016 at 1:03:05 PM

Hi guys,

Thanks for the great advice. Looks like I'm taking down some drywall this week end.


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